PSI - Issue 57

Dr.-Ing. D. Jbily et al. / Procedia Structural Integrity 57 (2024) 199–216 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

210 12

Fig. 12. Location and direction of analyses

The measures were carried out at a theoretical depth of 0, 10, 20, 30 and 80 µm. The results show that the residual stresses on the tooth dedendum are lower than those obtained on the tooth addendum. This can be explained by the greater damage caused by micropitting and wear, which has resulted in material removal and a reduction in the compressed surface layer.

Depth (µm)

-1000 -900 -800 -700 -600 -500 -400 -300 -200 -100 0

0

20

40

60

80

100

Residual stresses (MPa)

Dedendum-Longitudinal stresses Addendum-Longitudinal stresses

Dedendum-Radial stresses Addendum-Radial stresses

Fig. 13. Residual stresses profiles on the addendum and dedendum of a tooth after testing

4. Analytical Study The ISO/TS 6336-22 calculation method of the micropitting load capacity is based on the principle that micropitting occurs when the minimum specific film thickness of a gear is below a permissible value for the specific film thickness. So, the safety factor against micropitting is defined as the ratio between the minimum specific film thickness of the lubricant and the permissible specific film thickness of the lubricant.